(1) Field of the Invention
The present invention relates to a method of improving the physical properties of tetrazoles.
Compounds to be employed in the present invention, which are represented by the chemical formula (1) shown later and which have been discovered by the present inventors, can be improved in such physical properties as impact sensitivity and friction sensitivity with respect to conventional tetrazoles. Therefore, they are useful as less-toxic gas-generating agents for air-bags or as foaming agents for high polymers. As such, they are expected to be widely used as safe, easy-to-handle gas-generating agents or foaming agents for high polymers.
(2) Description of the Prior Art
Compounds of free radicals [5,5'-bi-1H-tetrazole (abbreviated as BHT hereinafter)] represented by the chemical formula (1) shown later have been utilized as gas-generating agents for air-bags or as foaming agents for high polymers. When a BHT compound is employed as a gas-generating agent for air-bags, it involves converting the compound into fine powder and loading it into a container for acceleration of its thermal decomposition. In such processes, due to its high impact and friction sensitivities, it may decompose during powdering or explode at the time of loading. When the BHT compound is used as a foaming agent for high polymers, on the other hand, it would be necessary to form master chips by adding the BHT compound to a thermoplastic resin with a melting point somewhat lower than that of the high polymer to be molded so that the BHT compound can be easily added to the polymer and that a preferable dispersion state of the compound into the high polymer to be molded can be obtained.